Image diagnoses can be mainly classified into morphological image data for observing changes in form and functional image data for observing changes in function. Morphological image diagnosis apparatuses for acquiring morphological image data include an X-ray diagnosis apparatus, an X-ray CT (Computed Tomography) system, an MRI (Magnetic Resonance Imaging) apparatus, and the like, while functional image diagnosis apparatuses for acquiring functional image data include a nuclear medicine diagnosis apparatus such as a PET (Positron Emission Tomography) apparatus and a SPECT (Single Photon Emission CT) apparatus.
The PET apparatus administers medical agents to a subject, the medical agents being labeled by a radio active isotope that discharges a positron. These medical agents are accumulated in an affected part such as a tumor of the subject, and the PET apparatus detects radiations generated when the positron discharged from the inside of a subject disappears. The affected part such as a tumor appears in PET image data acquired by this imaging. When the affected part of the subject is treated by the PET image data, the anatomical position information is not satisfied by the PET image data.
Therefore, recently, in order to acquire morphological image data and functional image data, a functional image/morphological image diagnosis apparatus, in which a morphological image diagnosis apparatus is combined with a functional image diagnosis apparatus, has been developed. For example, a PET-CT apparatus exists in which a PET apparatus is combined with an X-ray CT system (Patent Document 1.)
For example, the PET-CT apparatus has a gantry, a couch, a top, a couch horizontal transferring unit, a top horizontal transferring unit, and a top vertical transferring unit. The gantry has an aperture. A PET imaging position is displaced on the back side of the aperture, while a CT imaging position is displaced on the front side of the aperture.
The couch supports the top. The top is used for mounting the subject thereon. The couch horizontal transferring unit substantially horizontally transfers the couch. The top horizontal transferring unit substantially horizontally transfers the top to the couch. The top vertical transferring unit vertically transfers the top to the couch.
The substantially horizontal transfer of the couch with the couch horizontal transferring unit makes it possible to transfer the subject on the top to the CT imaging position and the PET imaging position. Thus, since the couch is entirely transferred upon imaging, deflections of the top become equivalent upon CT imaging and upon PET imaging.